Most Common Sites of Endometriosis Invasion
The ovaries are indeed the most common site of endometriosis, followed by the anterior and posterior cul-de-sac, posterior broad ligaments, and uterosacral ligaments. 1
Anatomic Distribution in Order of Frequency
The most common sites of endometriosis involvement, in decreasing order of frequency, are:
- Ovaries - the primary site of disease 1
- Anterior and posterior cul-de-sac 1
- Posterior broad ligaments 1
- Uterosacral ligaments 1
- Uterus (adenomyosis) 1
- Fallopian tubes 1
- Sigmoid colon 1
- Appendix 1
- Round ligaments 1
Deep Infiltrating Endometriosis Patterns
When considering deep infiltrating disease specifically, the distribution shifts slightly:
- Uterosacral ligaments and posterior compartment (retrocervical, rectovaginal septum, vaginal fornix) are detected with 88% sensitivity on MRI 2
- Intestinal involvement (primarily rectosigmoid anterior wall) is detected with 92.4% sensitivity on MRI 2
- Bladder wall endometriosis is less common, detected with only 50% sensitivity on MRI 2
Clinical Significance of Location
The posterior cul-de-sac and uterosacral ligaments are particularly important clinically because:
- These sites are associated with obliteration of the cul-de-sac, which can be identified by adhesions, fixed retroversion of the uterus, and low-signal intensity bands on imaging 3
- Deep infiltrating disease in these locations correlates with pain severity, unlike superficial peritoneal lesions 4
- MRI demonstrates 83.7% sensitivity for detecting cul-de-sac obliteration when bowel loops adhere to the posterior uterine surface 3
Bowel Involvement Specifics
For gastrointestinal tract endometriosis beyond the pelvis: